Coherer.



No. 763,894. PATENTED JUNE 28, 1904. W. S. HOGG.

GOHBRER. APiLIUATION rmm FEB. 9. 1903.

H0 MODEL.

UNITED STATES Patented June 28, 1904.

WILLIAM STETSON HOGG, OF WASHINGTON, DISTRICT OF COLUMBIA.

COHEREFL- SPECIFICATION forming part of Letters Patent No. 763,894, dated June Q8, 1904.

Application filed February 9, 1903. Serial No. 142,578. (No model.)

.To all whom, it may concern.-

Be it known that I, WILLIAM STE'rsoN H oeo, a citizen of the United States, residing at Washington, in the District of Columbia, have invented certain new and useful Improvements in Coherers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in receivers of electric waves for use in wireless telegraphy, and more especially to that class of receivers in which with imperfect contact there is an automatic decohering action. This decoheringaction I attain by the use of metallic or annealed selenium alone or in combinationwith metals in the form of selenids. Many selenids automatically decohere slowly; but selenids of iron and a selenid of German silver, nickel, copper, and zinc alloyedI have found excellent.

My improved receiver in one form consists of a stiff wire of German silver heated at the tip of the flame of a Bunsen burner, rubbed with selenium, and then heated over the flame to drive off excess of uncombined selenium and mounted in a suitable support in contact with a steel needle, which may be oxidized to a blue color. By treating the German-silver wire as above stated I produce a highly-crystalline mixture of selenids sensitive and selfdecohering in action.

I have found that a single contact on account of its ease of regulation is preferable, and selenium with metals farther apart in the thermo-electric scale give the best results. A steel or oxidized-steel needle in imperfect contact with a selenited surface of German silver or a selenited-steel needle in contact with carbon give superior results. Of these two I consider the former preferable on account of there not being the microphonic action occurring in the latter.

My invention consists also in the use of a combination of contacts of a different character from each other, such as selenited steel and carbon and steel and selenited German silver connected in series or shunt with the receiver-battery.

My invention consists, further, in the use of a receiver which will automatically decohere in combination with one which will not automatically decohere or which will only partially decoheresuch, for example, as a receiver having contacts of steel and selenited German silver and one having contacts of steel and aluminium, both receivers connected in series or multiple with the receiver-battery, or I may use instead of the receiver of steel and aluminium a coherer of the ordinary type or, indeed, any coherer which will not entirely automatically decohere.

My invention further consists in the novel combination and arrangement of parts hereinafter described, and more particularly pointed out in the accompanying claims.

Referring to the accompanying drawings, Figure 1 represents a form of my improved receiver in side elevation; Fig. 2, a front elevation of the same; Fig. 3, a diagram showing the receiver connected in a wireless-telegraph circuit; Fig. t, a diagram showing the use of two receivers connected in the receiverloattery circuit, and Fig. 5 a diagram showing one of my improved receivers connected in circuit with an ordinary coherer.

Similar letters refer to similar par ts throughout the several views.

In the forms of my invention shown in the accompanying drawings, a represents the receiver-contact, consisting of selenium or selenids of metalssuch as iron, German silver, nickel, copper, and zinc alloyed, and othersand b the contact, consisting of a'steel needle, preferably oxidized to a blue color, or one of these contacts may be selenated steel and the other carbon. The contact a is secured by a thumb-screw c in a projection d of a metal disk 6, fastened to an insulated upright f, mounted upon a suitable base 9. The contact I) crosses the contact a near its end where the two are normally in imperfect contact. The contact I) is soldered or'otherwise suitably securedzto a delicate spring I, secured, as shown, in the upper end of the metal upright c'. The degree of pressure between the contacts a and b is regulated by means of the screw j, which passes through the upper portion of the upright i and engages the spring 71. I The wires are connected to the receiver by means of suitable binding-posts k and Z.

In Fig. 3 I have shown one of the receivers connected in the receiving-circuit, where m represents the aerial wire; a, the earth-wire; 0, the local receiver-battery, and p 7) telephonereceivers, one on each side of the battery. The telephone-receivers in this case act also as choke-coils. Obviously I may, if desired, employ only one telephone-receiver.

In Fig. 41: I have shown two receivers a b and a b, connected in series in the receivingcircuit. In this case the contacts used in one of the receivers may be different from those used in the other. For example,the contacts (a b may be selenited German silver and steel, respectively, and the contacts a b selenited steel and carbon. If itis desired to have the contacts a 7) remain cohered and not automatically decohere, these contacts maybe made of steel and German silver, respectively, or any other substances which will cohere, but not automatically decohere. I may also use as the non-decohering receiver a coherer of the ordinary form-that is, an ordinary filings-coherer without a tapper or other device to make it decohere. The effects of adding the second receiver a 6 or ordinary coherer are, among other things, to increase the resistance of the batterycircuit and, in case the contacts of the added receiver are of dissimilar thermo electric metals, to more readily efl'ect changes in electromotive force, since at such dissimilar thermo-electric contacts there are changes of electromotive force as well as of resistance, and actual experiments have shown in such a case there is a relatively greater sound effect in the telephone-receiver. With a comparatively small resistance in the battery-circuit the batteries run down quickly and the responsive contacts of the receivers change their microphonic action, with the results that the sounds in the telephone receivers lose much of their clearness. With the high resistance there is a steady flow of current of very small amperage, which affects the batteries very slowly, and I have found that any changes of current or electromotive force are in this case much more readily detected by the telephone-receiver. Moreover, the changes in current, as actually shown by a milliampere-meter, are much less sudden and a great deal more regular with the high added resistance of the coherer or other receiver than without, so that a relay or its equivalent phone-receivers p 1), battery 0, and receiver a 7). Assuming that both receivers a Z) and. q are decohered and the switch 9' placed as shown in the diagram, then when an oscillation is developed in the vertical wiresay the oscillation intended for the call-this will traverse both receiver a b and coherer q and pass to earth by wire 01., causing said receiver and coherer to cohere, whereupon current from the battery 0 will operate the relay 8, which latter may be made to produce the callsignal or other signal in any desired manner. After the reception of the call -signal the switch 1' may be thrown over on contact r, where the relay will be shunted. The telephone-receivers will then respond to the receiver a 6, while the coherer q remains cohered. Any other receiver which will not automatically decohere may be substituted for the coherer q. Likewise any suitable receiver may be substituted for the telephonereceivers herein shown, since these constitute no part of my present invention.

What I claim as my invention is 1. In wireless telegraphy, a receiver having one or more responsive contacts consisting of a selenid of a metal.

2. In wireless telegraphy, a receiver having one or more responsive self-restoring contacts embodying selenium.

3. In wireless telegraphy, a receiver having a self-restoring contact formed by a solid body embodying selenium.

4. In wireless telegraphy, a receiver having one or more responsive contacts consisting of a selenid of a metal and one or more responsive contacts consisting of a metal of a different character.

5. In wireless telegraphy, a receiver comprising one or more responsive contacts of carbon and one or more responsive contacts of a selenid of a metal.

6. In wireless telegraphy, a receiver comprising one or more responsive contacts of steel and one or more responsive contacts of a metallic selenid.

7. In wireless telegraphy, a receiver comprising one or more responsive contacts containing selenium and one or more-responsive contacts of steel.

8. In wireless telegraphy, a receiver comprising one or more responsive contacts of carbon and one or more responsive contacts of selenited steel.

9. In wireless telegraphy, receiving apparatus comprising two or more wave-responsive contacts consisting respectively of oxidized steel and selenited German silver, and two or more wave-responsive contacts con sisting respectively of selenited steel and carbon.

10. In wireless telegraphy, receiving apparatus comprising two coacting wave-respom sive devices, one of which is self-restoring, and the other of which is not self-restoring.

11. In wireless telegraphy, receiving apparatus comprising .two coacting wave-responsive devices, one of which is self-restoring, and the other non-self-restoring, and a signal indicating device connected in circuit with 1 both devices.

12. In wireless, telegraphy, receiving apparatus, comprising two coacting wave-responsive devices one of which is self-restoring, and the other of which is non-self-restoring, a circuit common to both devices and a translating device connected in said circuit.

13. In wireless telegraphy, receiving apparatus, comprising .two wave-responsive devices, one of which is self-restoring, and the other of which is non-self-restoring, a circuit common to both devices, a relay connected in and operated by said circuit, and a telephonereceiver also connected in said circuit, said relay being adapted to produce the preliminary call, and means for rendering said relay non-responsive after the reception of the call, substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

WILLIAM STETSON HOGG. 

